2008 Nissan Altima Se Sedan 4-door 3.5l on 2040-cars

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Infiniti's new VC-T changes the rules of small turbocharged engines

The upcoming Infiniti QX50 crossover does not get our pulse racing, no matter how shapely the QX Sport Inspiration concept that previews it may be. No midsize SUV does, to be fair. But it has something special under the hood – the world's first production variable-compression-ratio engine. That means the QX50's 2.0-liter turbo four, which makes 268 horsepower and 288 pound-feet of torque, will have up to 27 percent better fuel economy. Here's how it works. The trend of moving to smaller, turbocharged engines carries with it one big falsehood. Under low load when the turbo isn't needed, these engines are less efficient than an equivalent engine without a turbo because of the low compression ratio the turbo requires. That is, if you never need the extra power, you're wasting fuel. Turbocharged (and supercharged) engines use a lower compression ratio to prevent detonation. When you force extra air in a cylinder and mix it with fuel, it's more likely to prematurely go boom. Lowering the compression ratio prevents this problem, but it's less efficient. Infiniti's VC-T promises the best of both worlds, with a compression ratio that ranges from 8.0:1 for high-power turbo needs to a 14.0:1 ratio for fuel-sipping efficiency. At its heart the VC-T engine is a simple idea, but it's complicated to explain. Consider yourself warned. The photo below from Infiniti serves as a good visual overview. For the truly nerdy, this patent application covers the mechanical concept. Instead of having the pistons connected to the crankshaft, Infiniti's engine has a pivot arm with a connection on each end. One end connects to the piston, the other connects to a second lower shaft, which is controlled by an actuator arm. At any given time the engine's pistons move up and down according to the lobes on the crankshaft. But the actuator arm can change the angle of the pivot arm up and down. That is, the pistons still move in the same motion with the same stroke, but phase the entire stroke up or down. Move the pivot up and there's less room at the top, which means a higher compression ratio. Move the pivot down and the compression ratio goes down, too. As an added bonus, the lower shaft eliminates the need for counter-rotating balance shafts. Infiniti says this system works constantly and can vary the compression ratio to any number between 8:1 and 14:1. It also uses electronic variable valve timing on the intake valves to switch into Atkinson-cycle combustion for greater efficiency.

Nissan Juke facelift spied during testing

The Nissan Juke boldly reinvented the subcompact crossover for the modern age a decade after the niche's progenitors - the first-generation Toyota RAV4 and Honda CR-V - grew well beyond their original, diminutive sizes. Since being introduced in 2010 as a 2011 model, the Juke has proven to be a huge sales success for Nissan in Europe and quite a success here, too. A modest refresh is planned for the 2015 model year of Nissan's tiniest crossover, and our spy shooters have caught an early glimpse.
The exact changes are not easy to spot, but you can bet that anywhere you see camouflage, a modestly new look is hidden underneath. The biggest change up front is the narrower grille that appears to no longer extend over the headlights. Assuming this isn't just a clever disguise, the change gives the impression that the Juke actually has distinct headlights, instead of massive fog lights. The more angular front air dam also appears to extend slightly lower than before, and the intakes appear to be revised as well.
The changes to the rear are even more minor. You can still see the outlines of the boomerang-shaped headlights, and any alterations to the rear bumper are impossible to spot behind the camouflage tape. It's also unclear at this point whether the interior will receive any refinements or new options.

NHTSA probing whether to call Nissan to the carpet over Versa unintended acceleration

The Nissan Versa and Versa Note may have a carpeting problem that could make the little cars risky to drive. The National Highway Traffic Safety Administration is launching a preliminary evaluation into the 2012-2014 model year versions of the Versa, Versa Sedan and Versa Note, affecting an estimated 360,000 vehicle. In these vehicles, it's possible that the driver's foot could be caught where the carpet meets a trim panel near the accelerator. The regulator has four reported instances of the issue, but it's still collecting data from Nissan about any further cases.
According to the complaints, the tunnel carpet cover trim panel can possibly snag the drivers' right shoe where it meets the carpet, and can either keep their foot on the accelerator or prevent moving it to the brake pedal. In one case, the problem was bad enough that the driver had to free his foot using his hand, while driving. In two of the four reported cases, the vehicles were rental cars.
This is actually the second ongoing preliminary evaluation for some of these models. In late May, NHTSA started looking into the 2013-2014 Versa and 2014 Versa Note for long brake pedal travel.